If issue not solved even after adding required DLL under ISAPI.-- Check web.xml under your project folder and see for any reference of ISAPI present or not. Above scenario may only happen when you have CF 10 already Installed and due to mismatch in handler mapping It cause to read wrong path of ISAPI DLL.-- If found in web.xml check config setting for ISAPI. Validate its path.

If you still facing any issue, Please share. It is also new to me.
Hope it may help :)